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Iodine is an essential nutrient for thyroid hormone production. Due to inadequate public health measures, mild-moderate iodine deficiency has become a re-emerging problem in many developed countries in the past decades. Insufficient consumption of iodine in pregnancy may lead to brain damage and a lower Intelligence Quotient (IQ) in children in comparison to children of mothers with adequate intake. Recent National Health and Nutrition Examination Surveys (NHANES) data have shown that even though the non-pregnant United States (U.S) population has adequate iodine intake, U.S pregnant women are currently mildly iodine deficient, with median urinary iodine concentrations (UIC) being 129 μg/L. In 2004 pregnant women who attended the Boston Medical Center (BMC) Antenatal Clinic were also mildly iodine deficient, with median UIC of 149 μg/L. These values were higher than the NHANES median UIC (129 μg/L) Due to national trends of mild-moderate iodine deficiency among pregnant women, and since in 2011 the American Thyroid Association recommended that prenatal vitamins contain 150 μg of iodine, in this study we aimed to determine if the iodine status among the BMC pregnant women has changed. We also aimed to assess consumption of iodine-containing foods, knowledge regarding iodine nutrition, and frequency of use of iodine-containing prenatal vitamins. We conducted a cross-sectional study targeting 125 women living in the Boston area attending the BMC Antenatal Clinic. To date, 61 women have been enrolled. Participants provided urine samples, and completed questionnaires about their recent food intake and demographic characteristics. The participants’ mean age was 31 ± 6.7 years and their median UIC was 145.5 μg/L (range 17.5 μg/L- 886 μg/L). As expected, UIC was positively associated with iodine supplement intake and recent consumption of iodine-rich foods (milk cheese) (p< 0.0001 for each), although these associations were not significant in multivariate analysis. No associations were observed between UIC and other factors such as age, race, education, use of multivitamins containing iodine in the past 24 hours, and whether health providers discussed iodine nutrition, possibly due to a small sample size. Our results indicated that the iodine status of pregnant women attending B.M.C remained mildly iodine deficient in the past decade despite the recommended measures to increase the iodine content in multivitamins. In our sample, 52.5% of the pregnant women who attended BMC were mildly iodine deficient with median UIC

In the United States, rate of preterm birth peaked in 2006 and little progress has been made to date despite ambitious Healthy People 2020 goals. Infants born premature are at higher risk of death and disability, including psychological conditions, learning difficulties and medical disabilities, than term newborns. Additionally, adverse birth outcomes are associated with asthma, the leading cause of chronic childhood illness and disability. According to the ‘Barker hypothesis’, intrauterine exposures may serve as a programming stimulus that alters the development of biologic systems and the risk or susceptibility to future disease. One such programming stimulus is maternal nutrition in pregnancy as previous research has shown associations between prenatal nutrition (such as vitamin supplement use and Special Supplemental Nutrition Program for Women, Infants and Children enrollment (WIC)) and birth and early childhood respiratory health outcomes. Through this dissertation, we address gaps in knowledge regarding supplement use in pregnancy and prenatal enrollment in the nutrition program among low-income, minority women, allowing for better informed public health messages. In the first study, we identified WIC eligible parous women who gave birth to first and second siblings between 2007 and 2011 from California electronic birth records to assess the impact of program enrollment on recurrent preterm birth. WIC eligibility in the second pregnancy was based upon both an income criteria (assessed through Medi-Cal as the second pregnancy primary payer for prenatal care) and “nutritional risk” (assessed through a premature first birth). We found that eligible second pregnancy non-enrollees had a higher risk of recurrent preterm birth than program participants among both first pregnancy WIC non-enrollees and first pregnancy WIC enrollees. These findings suggest that the benefits provided by WIC to patrons, including vouchers for food supplementation, counseling and referrals to health and social services, may improve birth outcomes of the women electing to enroll in the program. In sensitivity analyses, we also found the magnitude of this association was strongest for the following high risk subgroups of eligible women: first pregnancy Medi-Cal participants, younger, and Black or Hispanic mothers with the shortest time between births. The second study used data from a Los Angeles based case-control study nested within the 2003 birth cohort to assess the relationship between the timing of pre-natal supplement initiation and birth outcomes. This study limited analyses to non-Hispanic white and Hispanic women, the predominant racial/ethnic groups among respondents. Among Hispanic mothers, we observed an increased odds of preterm birth the later a woman initiated pre-natal supplement use in pregnancy and the magnitude of the association was larger in US-born compared to foreign-born women. The case-control respondents were followed approximately three years later to assess offspring respiratory outcomes. The third study objective was to assess whether adverse early childhood respiratory health is associated with the timing of folic acid supplement initiation in pregnancy. Among all study participants, timing of folic acid use (derived from reports of both folic acid and pre-natal supplements) was not associated with wheeze in the first three years of life, current wheeze, or lower respiratory tract infection in offspring even after re-weighing the population to account for premature birth and censorship. Among mothers with a history of eczema, hay fever or asthma, we found late folic acid supplement initiators had between 1.7-1.9 times the risk of adverse respiratory health outcomes compared to their first trimester initiating counterparts. No association was found among non-atopic mothers. In conclusion, our results support that prenatal nutrition in pregnancy may serve as a programming stimulus as timing of supplement initiation and nutrition program enrollment were found to be associated with offspring health. Both are potentially modifiable factors and the information obtained through these studies highlights the importance of tailored public health interventions for those at highest risk of adverse birth and childhood respiratory health outcomes.